[PATCH 1 of 3 STABLE V2] manifest: fix a bug where working copy file 'add' mark was buggy

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at fb.com>
# Date 1417042456 28800
#      Wed Nov 26 14:54:16 2014 -0800
# Branch stable
# Node ID b22e0b171d5c84fec5129a142806c708090d5c8e
# Parent  7f8d27e1f862819b6f13e368c949aa824de5ae45
manifest: fix a bug where working copy file 'add' mark was buggy

Because the same dictionary was used to (1) get node from parent and (2) store
annotated version, we could end up with buggy values. For example with a chain
of rename:

  $ hg mv b c
  $ hg mv a b

The value from 'b' would be updated as "<old-a>a", then the value of c would be
updated as "<old-b>a'. With the current dictionary sharing this ends up with:

    '<new-c>' == '<old-a>aa'

This value is double-wrong as we should use '<old-b>' and a single 'a'.

We now use a read only value for look up. The 'test-rename.t' test is impacted
because such chainly added file is suddenly detected as such.

diff --git a/mercurial/context.py b/mercurial/context.py
--- a/mercurial/context.py
+++ b/mercurial/context.py
@@ -1061,19 +1061,20 @@ class committablectx(basectx):
 
     @propertycache
     def _manifest(self):
         """generate a manifest corresponding to the values in self._status"""
 
-        man = self._parents[0].manifest().copy()
+        man1 = self._parents[0].manifest()
+        man = man1.copy()
         if len(self._parents) > 1:
             man2 = self.p2().manifest()
             def getman(f):
-                if f in man:
-                    return man
+                if f in man1:
+                    return man1
                 return man2
         else:
-            getman = lambda f: man
+            getman = lambda f: man1
 
         copied = self._repo.dirstate.copies()
         ff = self._flagfunc
         for i, l in (("a", self._status.added), ("m", self._status.modified)):
             for f in l:
diff --git a/tests/test-rename.t b/tests/test-rename.t
--- a/tests/test-rename.t
+++ b/tests/test-rename.t
@@ -582,11 +582,12 @@ overwriting with renames (issue1959)
   rename to d1/a
   diff --git a/d1/a b/d1/c
   copy from d1/a
   copy to d1/c
   $ hg update -C
-  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ rm d1/c # The file was marked as added, so 'hg update' action  was 'forget'
 
 check illegal path components
 
   $ hg rename d1/d11/a1 .hg/foo
   abort: path contains illegal component: .hg/foo (glob)